The state of the art is illustrated on the basis of FIG. 1 attached hereto, which schematically represents a single shuttle weave of a face-to-face fabric. For the weaving of a face-to-face carpet fabric according to the single shuttle weaving principle, a weft end (1) is alternately inserted in the lower fabric (OW) and in the upper fabric (BW). The first pick locates the weft (1) under the tight warp end (SO) of the lower fabric (OW). With the next pick the weft (1) is located above the tight warp end (SB) of the upper fabric. With the next pick the weft (1) is located above the tight warp end (SO) of the lower fabric (OW). The following pick locates the weft (1) under the tight warp end (SB) of the upper fabric (BW).
In order to weave the weft (1) to the tight warps SO and SB, one or more binding warps are added.
There are various known manners for interlacing these binding warps. The backing fabric is repeated every 4 picks, as is the case with the example in FIG. 1--when the backing fabric on pick 1-2-3-4 is repeated on pick 5-6-7-8, on pick 9-10-11-12, etc.
The numbering of each pick starts from the extreme left weft--consisting of a weft end (1) inserted in OW--which is referred to as pick 1, while following the fabric from left to right in FIG. 1, the successive wefts are referred to in sequence as pick 2, pick 3, etc. . . . The numbering is indicated vertically under each weft in the figure. The pile warp ends are indicated as P1, P2, P3, P4, P5.
These pile warp ends can take up 2 positions in relation to the rapier or in relation to the weft.
When the pile warp ends make no connection between the lower fabric (OW) and the upper fabric (BW), that pile warp end acts as dead pile, this pile warp end participates in the weave of OW, respectively BW, and relates to it as a woven-in pile warp end, or simply of a woven-in dead pile.
According to the state of the art the choice is made between remaining either woven-in, or to connect the fabrics e.g. OW resp. BW with the other BW resp. OW as working or pattern forming pile warp end after pick 2. When a pile warp--for example P1--acts as working pile in pick 1, this end P1 is lowered under the weft, while the other pile warp ends are raised above the weft. On pick 2 the pile warp end P1 will then be raised above the weft while the other pile warp ends are lowered under the weft. Color change should take place after pick 2 with P2 also woven into the lower piece. On pick 3 the working pile P2 will then first be lowered under the weft together with the woven-in pile warp ends (to which P1 now also belongs) of the lower carpet. Pile warp ends which are woven into the upper carpet are raised above pick 3. On pick 4 P2 is now raised above the weft I, woven into the upper fabric together with the colors. Colors woven into the lower fabric are below. The single shuttle weave is obtained according to this technique.
This single shuttle weave has the disadvantage that it shows so-called double workers. With the change over from a certain color formed by a pattern forming pile warp end which after this change over is woven into the upper fabric to another color formed by a pattern forming pile warp end which was woven into the lower fabric for this change over, a tuft runs from the ending color P4 together with the starting color P3 (see picks 15 and 16 in FIG. 1). These pile tufts of different color will be placed next to each other (in weft direction) and they are referred to as double workers. The separation line between these two color fields is unclear and shows a certain saw-tooth line.
From EP 175 963 it is known that in order to avoid these double workers the demarcation between the color fields can be improved by lowering the pile which is starting to be pattern forming (e.g. on pick 16--FIG. 1) under a weft. Because of this however a pile loop is eliminated. With this method a color point is made in the pointed-paper drawing per 4 picks (2 picks per carpet), because the weaving-in shows a repeat over pick 4.
For a pattern resolution of e.g. 4 rows/cm in the pointed-paper drawing 8 picks/cm must be made in the carpet.